The present application relates generally to the field of doors and more specifically to pneumatic doors for trailers and containers.
The delivery of perishable items presents many challenges. For instance, sea food is a highly perishable product. A variety of methods for preserving the freshness of sea food exist. In some cases, sea food is kept alive during transport. In other cases, sea food is refrigerated or frozen soon after it is extracted from the ocean and transported quickly to its final destination. Transporting sea food from coastal regions to land-locked regions presents significant health and safety challenges.
Meats are also a very perishable product. Meats may spoil within hours if they are not treated properly. As is the case with sea food, meats are refrigerated or frozen soon after animals are slaughtered and are stored at low temperatures during transport to avoid spoilage.
Many food products are stored below freezing (0° C. or 32° F.). For instance, frozen dinners are common items in supermarkets today. The dinners are prepared and stored at below freezing temperatures in order to avoid spoilage which might otherwise occur after production but before the dinner products are consumed. Fruits and vegetables are also often transported at near- or sub-zero temperatures in order to preserve freshness.
In addition to food products, pharmaceutical and chemical products are also subject to spoilage. For instance, many vaccines are stored and transported in temperature-controlled conditions in order to maintain their effectiveness.
The storage and transportation of these and other products often involves a temperature-controlled supply chain, or cold chain.
Additionally, foodstuffs, pharmaceuticals, and other chemical products—whether or not they need to be refrigerated—are potential targets of terrorists.